Thread-measuring device for sewing-machines.



0. L. LAWSON &J. H. REED.

THREAD MEASURING DEVICE FOR SEWING MACHINES.

APPLICATION FILED MAR. 24. ms.

1,245,935. I PatentedN0v. 6,1917."

2 SHEETS-SHEET l.

\X/I'I'NESSESZ I I -INVEN+IIWSI 0. L. LAWSON & J. H. REED.

THREAD MEASURING DEVlCE FOR SEWING MACHINES.

APPLICATION HLED'MAR. 24, 1915.

124.5935. Patented Nov. 6, 1917.

- 2 SHEETSTSHEET 2.

FEEL.

\X/ITNESSESl INVEN'i'Ell SI iin'rrnn sas ar 'OSGAB L. LAWSON AND I-I. REED, 0 LYN'N, MASSACHUSETTS.

'rnREAn-MEAsUnmG DEVICE ron snwiive-maonnvnsi Application filed March*24,:1915.' Serial No. 16,767.

To all whom it may concern: s I

Be it known that we, OSQAR-L.'LAWSON, a subject of the King of Sweden, and JAMES H. REED, a citizen of the United States, residing at Lynn, county of Essex, State, of-

son, filed August '27, 1914, sa. No."'858,825

which eventuated into Pat. No.- 1,217,871, Feb. 27, 1917. In that application there is shown a thread measuring and locking mechanism which is controlled by the position of the presser foot 'so that a proper length-of thread for the formation of the stitch' is fed in spite of variations in the thickness Of'the stock which is being operated upon; The present inventionaii'ords-a positively operated mechanism for accomplishing this pur pose and does away with the'employment of springs so that the operation of the device is more certain and eflicientthan that shown in the application previously referred to.

This makes it possible to runthe machine at a high rate'of speed without-diminishing the efl'ectivenessof the thread measuring and locking mechanism.

The invention will be fully understood from the following description when taken in connection with the accompanying drawings and the novel features thereof willfbe pointed out and clearly defined in the claims at the close of 'this specification.

1 Inlthe drawings, Figure '1 is a side elevation of a machine embodying our invention. Fig. 2 is a view of the parts shown in'the lower part of Fig. 1 said parts being shown in the position which they occupy at the time when'the thread measuring arm'is lifted. Fig. 3 is affront elevationof theparts shown in Fig. 2.

Referring to the drawingsfand' particularly to Fig. 1, there is shown "at '11; the presser foot having'a tail 12 the whole being pivoted at 13. It will be seen that whenthe presser foot is raised, either'by hand 'forthe insertion of the work, or periodically during the feed'of the work, the tail of-the presser foot will be correspondingly 1owered.- Ae- Specification of Letters Patent..-

had therein'to the accompanying draw- Patented Now 6, 1917.

cordingly'there is connected to the tail of the presser foot a connecting ro'd 14',the position of the lower end of which determines the amount-of thread delivered to the stitch forming mechanism. The upper end of the connecting rod is attached to the tail of the presser foot by means of anadjustingscrew 15 passing through a thimble 16 in a lug formed onthe'tail of the presser foot. The other end of the screw-engages anotherlug on the presser foot. The screw threaded portion of thescrew '15 passes through a collar 17 to'which the connecting rod l lis pivoted at118. It. will therefore be seen that when the screw 15 is rotated, the collar 17 will b'e move'd toward' or away'from the pivot13 about which the presser foot moves, and that the amplitudeof movement "ofl'the connecting rod 141 will be correspondingly varied.

At 19issliownfa shaft on which is located a cam 20 having acam groove 21 infwhich travelsa cam roll 22' on'one end of a lever 23 pivoted-at 2 1 toftheiframe'of the machine.

The rotation of the sca 1nf2 0 gives a positive motion ofjuniform amplitude to the lever 23 in 'timewith thelother parts of the 'mach ine. The front end of the lever23 isfprovi'ded with a downwardlyextenjding pin 25 at sub;- stan'tially right angles 'to the length: of the lever'23. This pin 25 passes throughla'hole 26in a head 27 pivoted at 28 to the lower end of the connecting rod 141 i "The hole is coun tersunk or bored out as shown .in dotted linesin Fig. ljso that the lever 23 is'free to swing about-its pivotj2 l without causing the pin 25 to bindinthehole 26. It will be seen that each time the lever 23 is oscillated bythe 'cam' 20 the pin 25 pulls the head-27 to-the left as shown in" Fig. '1 (see .also Fig'.'* 2) an amount depending on the height at which the headv27 is then held by the connecting rod 14.

v 29, is shown -a hole similar tothe hole 26 and throughthis'holepasses apin 30 forming one arm of a bell crank lever, the

other arm of which is designated 31. This bell "crank 'leve'r is pivoted at 32 and terminates at its front end in a'half round thread measuring arm, 33 extending. atri'ght angles to',the"lever'3l.'gf Beneath this half round threadengaging member '33,i s located a secondhalf round member 34; on anarm 35 also fp'ivoted at 32 to the frame fof the machine. For convenience this "member may :be termed the thread 'i 'l heset'two half round members 33""and'343 rest upon a fiXedpin BB snattethradtiampsr is held.

in contact with the fixed pin by a spring 37. The lever 35 on which is placed the thread clamp 34 is ext-ended rearwardly as shown at 38 and provided with an adjustable pin 39.

The thread a, see Fig. 2, to be fed passes from the cop or spool of thread under the thread clamp 34 around the two half round portions and down into the wax-pot not shown, from which it is carried to the stitch forming mechanism. It will be seen that the spring37 clamps the thread as comes from the cop firmly but gently between the fixed pin 36 and the thread clamp 35%. Each time the cam 20 revolves the movement of the lever 23 pulls the head 2? to the left and lifts up the thread measuring arm 33 a distance depending upon the position vertically of the head 27. The position occupied by these parts at the time when the head 27 has been drawn to the leftis shown in Fig. As the end of the thread which passes down to the wax pot is at this time held firmly by the work, the upward movement of the thread measuring arm 33 draws a portion of the thread through between the lower thread engaging :lever 34: and the fixed pin 36 thus measuring off the proper amount for the. formation of the next stitch. The two thread engaging members then close. It will be seen that the extent to which the two thread engaging members 33 and 3.4 are separated will depend upon the position of the presser. foot 11 which will lower the head 27 an amount proportional to the amount which the presser. foot is raised by. any increase in thickness in the work. The lowering of the head 27 increases the distance from the pivot 24 to the point ofcontact between the pin 25 and the cross head 27. It also shortens the distance between the cross head 27, and the pivot 32, about which the thread measuring arm moves. Adjustment is easily accomplished by turning the screw 15, thereby changing the ratio between the movement of the presser head and the movement of the cross head 27. The pin 39 provided so that when the presser foot is lifted up, for the insertion or removal of the work, the cross head 27 will be brought into engagement with the upper end of said pin 39 and ivill liftnp the thread clamp 34 so that it will no longer pinch the thread against the fixed pin 36, and the thread will then be free to be drawn out.

The construction just described is positive in its operation and the parts are so. constructed that a uniform operation results regardless of the speed at which the. machine is run. This is a matter of considerable importance because it has been found in actual practice that there is a tendency of the machines to, feed the thread differently at different rates of speed.

What we claim 1. combination with a presser. foot, an

' two armed lever fulcrumed intermediate its ends, one arm of said lever forming a thread measuring arm and the other arm havlng a loose shdmg connection with said cross head,

said loose connection. permitting movement of the cross head. with relation to the, fulcrum point of said lever thereby varying the throw of the thread measuring arm, another lever fulcrunied intermediate its ends, one

arm of which has a finger which has a loose v sliding connection with said cross head, and a cam having. operative connection with said other arm of the. last mentioned lever where.- by the lower. end of said connecting rod is oscillated and thereby the thread measuring arm is actuated.

In. combination w t a P esser foot, an arm on one. end of which said presser foot is mounted, a downwardlyextending connecting rod pivotally connected at its upper end with said arm, said presser foot arm being fulcrumed at a point between the. presser foot and the pivotal connection of saidv rod with said arm, a head pivotally connected with the, lower. end of said rod, a lever fulcrumed intermediate its ends, one, arinof said lever. forming a thread measuring arm and the other. arm being loosely connected with said head, said loose connection. permitti ng movement of the head with relation to the fulcrum point ofsaid lever, thereby varying the throw of the thread measuring arm, another lever. f-ulcrumed intermediate its ends one, arm of which has a loose. connection with said head, and a cam. having operative. connection with the. other arm of said last mentioned lever whereby said last mentioned lever is given a uniform amplitude of movement on its fulcrum and by its connection with said head oscillates the lower end of said connecting rod, and thereby actuates the thread measuring arm.

3. In combination with a presser foot, an

arm on one end of which said presser foot is mounted, a downwardly extending connecting rod; pivotally connected at its upper end with said arm, a cross head pivotally connected with the. lower end of said rod, a two armed lever fulcrumed intermediate its ends, one arm of said lever forming a thread measuring arm and the other arm having a loose sliding connection with said cross head, said loose. connection permitting movement of the cross head with relation to the fulcrum point of said; lever thereby varying the throw of the thread measuring arm, another lever fulcrumed intermediate its ends, one arm of which has a finger which has a loose, sliding connection with said clfOSs head, a cam having operative. connection with said other arm of the last mentioned lever whereby the lower end of said connecting rod is oscillated and thereby the thread measuring arm is actuated, a pivoted thread clamp, and a stop pin connected with said thread clamp which is adapted to be engaged by the cross head in its downward movement when the presser foot is lifted to thereby turn the said thread clamp on its pivot and release the thread.

4. In combination with a presser foot, an arm on one end of which said presser foot is mounted, a downwardly extending connecting rod pivotally connected at its upper end with said arm, a cross head pivotally connected intermediate its ends with the lower end of said rod, a lever fulcrumed in termediate its ends, one arm of said lever forming a thread measuring arm and the Copies of this patent may be obtained for other arm having a loose connection with one end of said cross head in such manner as to permit movement of the head with relation to the fulcrum point of said lever, another lever fulcrumed intermediate its ends, one arm of which has a loose connection with the other end of said cross head in such manner that the cross head is movable with relation to the fulcrum of said mentioned lever and means for oscillating said last mentioned lever on its fulcrum and thereby actuating the thread measuring arm.

In testimony whereof we affiX our signatures, in presence of two witnesses.

OSCAR L. LAWSON. JAMES H. REED. Witnesses:

GEORGE P. DIKE,

ALICE H. MORRISON.

five cents each, by addressing the commissioner of Patents, Washington, D. 0. 

